A complex Excel 2007 workbook could require multiple sheets. By default, Microsoft provides three sheets on each workbook, but you can add as many as you need.

Thankfully, Excel makes it easy to hide or unhide rows and columns, allowing you to declutter your spreadsheet and focus on the information that matters most.

How to Calculate Average on Excel From Multiple Sheets. Microsoft Excel 2010 provides a formula for calculating the average value from multiple worksheets in a workbook.